Teach Your Monster to Read
This is a great app that can currently be downloaded for free that helps children with their phonics, this is DfE approved:
Apple (free): https://apps.apple.com/gb/app/teach-your-monster-to-read/id828392046
Google (0.99p as Google will not allow it to be free): http://bit.ly/2cohkeR
PC version (free): https://www.teachyourmonstertoread.com/